Sarcopenia as a potential cause of chronic hyponatremia in the elderly

Associations between Baseline Hyponatremia and Activities of Daily Living and Muscle Health in Convalescent Stroke Patients

Objectives

Evidence is scarce regarding the association between hyponatremia and functional outcomes among older hospitalized patients. We aimed to evaluate the associations between baseline hyponatremia and improvement in activities of daily living (ADL) and muscle health in hospitalized post-stroke patients.

Methods

This retrospective cohort study included hospitalized post-stroke patients. Serum sodium concentrations were extracted from medical records based on blood tests performed within 24 h of admission, with hyponatremia defined as a serum sodium concentration below135 mEq/L. Primary outcome was the discharge ADL as assessed by the motor domain of the Functional Independence Measure (FIM-motor) and its corresponding gain during hospitalization. Other outcomes encompassed the discharge scores for skeletal muscle mass (SMI) and handgrip strength (HGS). Multivariate linear regression analyses were used to determine the association between hyponatremia and outcomes of interest, adjusted for potential confounders.

Results

Data from 955 patients (mean age 73.2 years; 53.6% men) were analyzed. The median baseline blood sodium level was 139 [interquartile range: 137, 141] mEq/L, and 84 patients (8.8%) exhibited hyponatremia. After full adjustment for confounders, baseline hyponatremia was significantly and negatively associated with FIM-motor at discharge (β=-0.036, P=0.033) and its gain during hospital stay (β=-0.051, P=0.033). Baseline hyponatremia exhibited an independent and negative association with discharge HGS (β=-0.031, P=0.027), whereas no significant association was found between baseline hyponatremia and discharge SMI (β=-0.015, P=0.244).

Conclusions

Baseline hyponatremia demonstrated a correlation with compromised ADL and muscle health in individuals undergoing rehabilitation after stroke.

Hyponatremia and malnutrition: a comprehensive review

BACKGROUND

Hyponatremia (serum sodium lower than 135 mmol/L) is the most frequent electrolyte alteration diagnosed in medical practice. It has deleterious clinical effects, being an independent predictor of mortality. Malnutrition encompasses pathological states caused by both nutrients excess and deficiency, being frequently documented in chronic kidney disease patients. In addition, chronic hyponatremia promotes adiposity loss and sarcopenia, while malnutrition can induce hyponatremia. This pathological interaction is mediated by four main mechanisms: altered electrolyte body composition (low sodium, low potassium, low phosphorus, or high-water body content), systemic inflammation (cytokines increase), hormonal mechanisms (renin-angiotensin-aldosterone system activation, vasopressin release), and anorexia (primary or secondary).

CONCLUSION

Malnutrition can induce hyponatremia through hydro-electrolytic, hormonal, inflammatory, or nutritional behavior changes; while hyponatremia per se can induce malnutrition, so there is a pathophysiological feedback between both conditions.

Relationship between serum sodium level at dialysis initiation and all-cause mortality

BACKGROUND

Hyponatremia is a common electrolyte disorder in patients with chronic kidney disease. In addition, hyponatremia is associated with mortality in patients with chronic kidney disease, including those on dialysis. However, few studies have examined this relationship in patients with incident dialysis.

METHODS

We used a database of multicenter prospective cohort studies that included 1520 incident dialysis patients. The baseline was set at the time of dialysis initiation. The enrolled patients were classified into five groups according to their serum sodium levels (< 130 mEq/L, 130-134 mEq/L, 135-139 mEq/L, 140-144 mEq/L, and ≥ 145 mEq/L). Multivariate Cox proportional hazards analysis was conducted to determine factors associated with all-cause mortality.

RESULTS

A total of 392 all-cause deaths occurred during the follow-up period. The ultrafiltration volume per body weight during the first dialysis session was more significant in the groups with the lowest and highest sodium levels. The percentage of patients using loop diuretics and thiazide was higher in the group with lower sodium levels (< 130 mEq/L and 130-134 mEq/L). All-cause mortality was significantly different among the five groups (p = 0.025). Multivariate analysis indicated that all-cause mortality was significantly higher in the group with the lowest sodium level compared to the group with a serum sodium level of 135-139 mEq/L (hazard ratio: 1.61, 95% confidence interval: 1.04-2.49).

CONCLUSION

Hyponatremia of < 130 mEq/L at dialysis initiation was significantly associated with all-cause mortality. We considered the results relevant to underlying conditions, including cardiovascular disease and medications.

Mildly Low Serum Sodium Levels in Chronic Liver Disease: At Risk for Sarcopenia and Portal Hypertension

OBJECTIVE

Hyponatremia and sarcopenia in advanced chronic liver disease (ACLD) are both associated with portal hypertension (PHT) and worse prognosis. This study investigated their interrelationship.

METHODS

This retrospective study analyzed 751 patients with CLD who underwent magnetic resonance elastography (MRE) at Nippon Kokan Hospital (Kawasaki, Japan). Patients were classified and studied in five groups based on serum sodium (Na) levels: <135, 135-136, 137-138, 139-140, and >140 mEq/L. PHT was assessed by thrombocytopenia, varices, and ascites, and magnetic resonance imaging (MRI) data were used to diagnose sarcopenia.

RESULTS

The proportions of the five groups were 3/4/13/32/48 (%), and the mean liver stiffness (LS) was 6.6/5.7/4.2/3.2/3.2 (kPa), with significant progressive increases at Na < 139 (p< 0.01). The incidence of all PHT events and sarcopenia also increased at <139 (each p < 0.01). By contrast, the LS thresholds for predicting thrombocytopenia, varices, and ascites increased from 3.5 to 4.7 and 5.1, respectively, and were the same at 3.4 for low Na (<139) and sarcopenia (all p < 0.01). Multivariate analysis of factors associated with low Na identified LS and sarcopenia as independent factors (p < 0.05 both). In the Cox proportional hazards model, low Na was a significant prognostic factor in ACLD (hazard ratio (HR) 5.33, p < 0.01); however, the albumin-bilirubin (ALBI) score (HR 2.49) and sarcopenia (HR 4.03) were extracted in the multivariate analysis (p < 0.05 both).

CONCLUSIONS

Studies using MRE imaging showed that low Na levels in CLD are associated with worse prognosis, not only due to elevated LS (i.e., PHT) but also the strong association with sarcopenia.

An analysis of patients with a chief complaint of difficulty moving

Objective: There have been few reports in English medical journals analyzing patients with difficulty moving. Herein, we conducted a retrospective survey of emergency patients admitted to our hospital with the chief complaint of difficulty moving, to clarify the clinical characteristics of the frequency, causative disease, and outcome in these patients. Patients and Methods: Between August 2017 and October 2021, we surveyed the patient database maintained by our department, covering cases in which the main complaint at the time of patient transport by ambulance to our hospital was difficulty moving. Results: In 111 cases, the patient's primary complaint was difficulty moving or adynamia. Patients included 59 males and 52 females, with a mean age of 76.3 years old. The most frequent diagnosis in these patients was rhabdomyolysis, followed by infection, body temperature abnormalities, electrolyte disorder, blood glucose abnormality, hypoxia, and renal failure. Trauma and various other diseases, such as stroke and malignancy, were also found to be causative diseases. After discharge from the hospital, the number of patients with a dependent status was greater than those with an independent status. Conclusion: Patients with difficulty moving were primarily elderly, and had a variety of causative diseases. Therefore, multiple approaches are required to manage these patients.

Preoperative hyponatremia and survival after left ventricular assist device implantation

BACKGROUND

Hyponatremia is associated with adverse outcomes in heart failure and after cardiac surgery. We hypothesized that hyponatremia is associated with poorer short-term and longer-term survival in patients after continuous-flow left ventricular assist device (CF-LVAD) placement.

METHODS

We reviewed a single-center database of patients who received a CF-LVAD during 2012-2017. Sodium (Na) values obtained within 14 days before CF-LVAD insertion were averaged; patients (n=332) were divided into hyponatremia (mean Na <135 mEq/L; n=160; 48.2%) and normonatremia groups (mean Na 135-145 mEq/L; n=172; 51.8%). Patients requiring preoperative dialysis or pump exchanged were excluded. We compared outcomes between preoperative hyponatremia and normonatremia groups.

RESULTS

The two groups' baseline characteristics were similar, although hyponatremia patients more often had preoperative mechanical circulatory support (44.4% vs 31.4%, p=0.002). Although hyponatremic and normonatremic patients did not differ in 30-day mortality (7.5% vs 6.5%, p=0.7), preoperative hyponatremia was associated with greater 5-year mortality (61% vs 44%, p=0.03). On binary logistic regression analysis, the strongest independent predictors of late mortality were hyponatremia (odds ratio [OR] 1.88, 95% CI [1.07-3.31], p=0.02), older age (OR 1.03, 95% CI [1.01-1.05], p=0.01), and elevated mean right atrial pressure/pulmonary capillary wedge pressure ratio (OR 4.69, 95% CI [1.76-12.47], p=0.002).

CONCLUSIONS

Hyponatremia was not associated with greater early mortality but was associated with poorer late survival. Optimal timing of LVAD implantation in relation to hyponatremia, and whether correcting hyponatremia perioperatively improves long-term survival, should be investigated.

Hyponatremia in the frail

As the lifespan increases, special attention has been given to the supportive care needs of the elderly. Frailty is an important issue in third age, since it is related to poor quality of life and mortality. The prevalence of pathological conditions related to sodium levels, specifically hyponatremia, is also present in the elderly. Yet, it is unclear, if hyponatremia and frailty are related to each other. This review summarizes the current state of knowledge regarding hyponatremia and frailty and analyzes five independent studies which searched for an association between those two parameters. As indicated by this study results, hyponatremia consists a risk factor for frailty. This could be explained by an effect of hyponatremia on sarcopenia and on cognitive function, which consist components of frailty. Thus, it is essential to monitor sodium levels in the elderly and to develop related interventions (e.g. using arginine vasopressin antagonists) in order to prevent frailty.

Mild hyponatremia is associated with low skeletal muscle mass, physical function impairment, and depressive mood in the elderly

Background

Mild hyponatremia (serum sodium 130–135 mEq/L) is a common electrolyte disorder in the elderly. However, its association with both sarcopenia and cognitive function remains to be clarified. Therefore, here we investigated the association of mild hyponatremia with skeletal muscle mass, physical function, and cognitive function in the elderly.

Methods

We enrolled 75 participants with mild hyponatremia and 2907 with normonatremia (serum sodium, 136–145 mEq/L) aged ≥70 years who visited the Memory Disorder Outpatient Center of Japan’s National Center for Geriatrics and Gerontology. Skeletal muscle mass index (SMI), grip strength (GS), walking speed (WS), one-leg standing (OLS) test times, and neuropsychological test scores were determined.

Results

One-way analysis of covariance showed that elderly participants with mild hyponatremia had lower SMI (7.1 ± 0.2, 7.2 ± 0.2 kg/m², p = 0.04), weaker GS (19.1 ± 1.9 vs 21.4 ± 1.8 kg, p = 0.01), slower WS (0.9 ± 0.1 vs 1.1 ± 0.1 m/s, p = 0.001), and higher GDS- 15 score (6.4 ± 0.9 vs 5.2 ± 0.9, p = 0.002) than those with normonatremia. Multiple logistic regression analysis indicated that mild hyponatremia was independently associated with sarcopenia (odds ratio [OR]: 2.2, p = 0.02), slower WS (OR: 5.3, p = 0.04) and shorter OLS time (OR: 2.5, p = 0.02) as well as with severe depressive mood (OR: 2.6 p = 0.006) but not with SMI (OR: 1.6, p = 0.2) or GS (OR: 1.9, p = 0.09).

Conclusions

Our results suggest that elderly people with even mild hyponatremia had physical function impairment and depressive mood.

Estimation of homeostatic dysregulation and frailty using biomarker variability: a principal component analysis of hemodialysis patients

Increased intraindividual variability in several biological parameters is associated with aspects of frailty and may reflect impaired physiological regulation. As frailty involves a cumulative decline in multiple physiological systems, we aimed to estimate the overall regulatory capacity by applying a principal component analysis to such variability. The variability of 20 blood-based parameters was evaluated as the log-transformed coefficient of variation (LCV) for one year’s worth of data from 580 hemodialysis patients. All the LCVs were positively correlated with each other and shared common characteristics. In a principal component analysis of 19 LCVs, the first principal component (PC1) explained 27.7% of the total variance, and the PC1 score exhibited consistent correlations with diverse negative health indicators, including diabetes, hypoalbuminemia, hyponatremia, and relative hypocreatininemia. The relationship between the PC1 score and frailty was subsequently examined in a subset of the subjects. The PC1 score was associated with the prevalence of frailty and was an independent predictor for frailty (odds ratio per SD: 2.31, P = 0.01) using a multivariate logistic regression model, which showed good discrimination (c-statistic: 0.85). Therefore, the PC1 score represents principal information shared by biomarker variabilities and is a reasonable measure of homeostatic dysregulation and frailty.

Nutrition and Sarcopenia-What Do We Know?

Muscle health is important for the functionality and independence of older adults, and certain nutrients as well as dietary patterns have been shown to offer protective effects against declines in strength and function associated with aging. In this paper, micronutrients, macronutrients, and food groups have been reviewed, along with their studied effects on the prevalence and incidence of sarcopenia, as well as their ability to preserve muscle mass and optimize physical performance. Randomized controlled trials appear to suggest a critical role for dietary intake of protein in preventing sarcopenia and muscle loss, although the optimal dose and type of protein is unknown. There are some promising data regarding the role of vitamin D and sarcopenia, but it is unclear whether the dose, frequency of dose, or length of treatment impacts the efficacy of vitamin D on improving muscle mass or function. Selenium, magnesium, and omega 3 fatty acids have been studied as supplements in clinical trials and in the diet, and they appear to demonstrate a potential association with physical activity and muscle performance in older individuals. Following the Mediterranean diet and higher consumption of fruits and vegetables have been associated with improved physical performance and protection against muscle wasting, sarcopenia, and frailty.